Thermostats have been used for many years as a temperature sensitive switch which controls heating and/or cooling equipment for conditioning a space in which the thermostat, or a temperature sensor connected to the thermostat, is placed. In the well known manner, a simple thermostat can be adjusted to establish a temperature set point such that, when the temperature in the conditioned space reaches the set point, the thermostat interacts with the heating and/or/cooling equipment to take suitable action to heat or cool the conditioned space as may be appropriate for the season.
Modern thermostat systems, which take advantage of the ongoing rapid advances in electronic technology and circuit integration, have many features which provide more precise supervision of the heating and/or cooling equipment to achieve more economical and more comfortable management of the temperature of a conditioned space. Many modern thermostat systems include a real time clock, a memory and a data processor to run a process control program stored in the memory to accurately measure the temperature of a temperature sensor disposed in the conditioned space and to send control signals to the heating and/or cooling equipment to closely control the temperature of the conditioned space. Modern thermostat systems permit anticipating and minimizing hysteresis or overshoot of the temperature in the conditioned space. In addition, the program can specify different set points at different times of the day and week and may also include a “vacation” mode which employs different set points when the conditioned space is not occupied for an extended period.
Many modern thermostat systems are programmable by a user. Typically, prior art programmable thermostat system employ a tactile touch pad with various fixed position buttons to be touched in a precise sequence to program set points (which may vary with the day of the week) for programmable time periods which may include a vacation mode. The programming sequence may be followed on a separate display, typically a liquid crystal display.
Outside of the art of programmable thermostat systems and programmable thermostats, dot matrix LCDs, which have pixel display elements arranged in rows and columns, are widely used. Dot matrix LCDs are not common as user-visible displays on programmable thermostats for viewing alphanumeric and iconic graphic information although such a thermostat is disclosed in, and particular features claimed in, co-pending U.S. patent application Ser. No. 10/440,474, filed May 15, 2003, and entitled: “Reverse Images in a Dot Matrix LCD for an Environmental Control Device” by Howard B. Rosen, incorporated by reference herein.
This limited use of dot matrix LCDs in programmable thermostats is because of basic engineering and practical considerations. Displayed information for a programmable thermostat generally includes such things as environmental conditions, heating and/or cooling equipment operation or non-operation, operational modes of the thermostat and the like. The most important information in thermostat displays is capable of being formed from segmented alphanumeric characters on less expensive LCDs without dot matrix capability and with reduced requirements for memory and programming.
Thus, dot matrix LCDs have not been widely used in prior art user programmable thermostats through a failure to understand an extended functionality capability of those devices when dot matrix LCDs are employed with a touch pad to effect an interactive display. This extended functionality is exploited to advantage in the present invention both to greatly simplify user programming and to relieve the manufacturer of the necessity to fabricate variants of the thermostat to suit the control and display aspects of various heating and/or cooling environments.
It is well known that information or operational interfaces of programmable thermostats can be incomprehensible or overly challenging to many users with advanced age, learning skills, poor vision and others in similar circumstances. Devices such as programmable thermostats, desktop computers, programmable VCR's, and even programmable clock radios often lie un-used in an owner's home because of fear of the complexity of such devices. More specifically, programmable thermostats generally comprise a user interface that use a mixture of raised push buttons with representations of environmental sensor information and control data on a segmented liquid crystal display.
In a modern programmable thermostat, a user is most often challenged with a first set of push buttons that lie outside of hinged cover and a second set of buttons that lie behind that hinged cover. External push buttons are usually those that a user will most often use to make simple program changes while the covered push buttons are lesser used buttons representing lesser used and usually more complex programming options. A user cannot by intuition selectively pick which push buttons represent thermostat program functions that are critical to a user and which buttons are of little consequence.
Some modern thermostat systems incorporate a touch sensitive screen which incorporate representations of buttons which a user may press as part of an interface with the thermostat system. While changing pressure sensitive buttons of a user interface from their more typical spring biased, mechanical form to a more convenient display-located representation, our knowledge of improvements in user interfaces and thermostat system equipment changes and control options are continuously evolving. At a particular moment in time, a form of a user interface may best suit a user's needs and incorporate modern equipment options. However, the day always arrives when an improved user interface is conceived or space conditioning equipment is improved, where either or both require a change in the thermostat system and/or user interface. Thermostats have in the past had very limited ability to be upgraded due to downward price pressure in the marketplace and the practical limitations of a user's lack of inclination to learn a sophisticated interface. A personal computer can accommodate many new programs and functions with its standardized user interface but is inconvenient, too large, and too costly for wall mounting typical of a modern thermostat.
There is a need for a programmable thermostat whose user interface can be easily changed after installation to accommodate equipment or control options not anticipated at installation or to change the user interface to a form not possible with a control program originally installed with the thermostat.